1. Field of the Invention
This invention generally relates to a training apparatus for firefighters, and more specifically, to a method and apparatus for training firefighters to deliver a proper amount of water through a given length of fire hose, without the need to lay out long lengths of fire hose during training exercises by inserting a disk into a fire hose to create a friction loss in the fire hose.
2. Related Art
Firefighting is a complex activity which involves a number of separate skills. As with any activity requiring a high level of skill, practice helps firefighters learn and improve these skills. One such skill is pumping a proper amount of water from a pump, through a given length of fire hose, to deliver a desired amount of water from the nozzle of the hose. To effectively combat fires, a specific quantity of water must be delivered to the nozzle of the hose. The volume of water delivered through fire hose is affected by the length of the fire hose used.
As water travels through the fire hose, it is slowed by the distributed frictional resistance encountered along the interior surface of the fire hose. The degree to which the water is slowed is sometimes referred to as "friction loss." Due to this friction loss, water pressure along the hose is gradually reduced. The water pressure loss due to friction loss is cumulative; the longer the hose, the more friction loss.
A fireman operating the pump which provides water must supply a proper amount of water from the water pump to the fire hose to overcome this friction loss in order to provide a proper volume of water to the nozzle. This is achieved by increasing water pressure from the pump as the length of the fire hose is increased.
When multiple lengths of fire hose are attached to create fire hoses of different lengths, the delivery of a proper volume of water becomes an especially complicated task. The only way for a firefighter to become proficient at this skill is to practice with hoses of different lengths. For this reason, each practice, or drill, usually involves several firefighters laying out several hundred feet of hose to simulate the conditions encountered under typical firefighting conditions. After the drill is completed, the fire hose must be picked-up.
If there were a way to simulate various long lengths of fire hose without actually laying out the lengths of the fire hose, it would greatly reduce the time spent for such practice sessions.
Accordingly, what is needed, and has not heretofore been provided, is a method and apparatus for simulating pumping water through a large length of fire hose without the necessity of laying out large lengths of fire hose.
Examples of previous efforts at manipulating water flow include:
Johnston et al., U.S. Pat. No. 4,995,646 (1991) discloses a connector assembly for permitting sealed passage of tubular lines through portions between separate chambers. The connector assembly comprises a first fitting body having a through passage for connection to one of the chambers. The through passage has an outwardly open end with a circumferentially and continuously conical mouth. A rigid disk member with a conical outer surface and regularly spaced circular openings is received in the conical mouth.
Flamm et al., U.S. Pat. No. 4,691,769 (1987) discloses a sealing means for shell and tube heat exchangers which only makes use of components which are external to the heat exchanger shell. These components mechanically compress a series of rubber type gaskets and incompressible tube sheets to thereby seal the tube to the tube sheet joints in such a manner to precisely control the degree of compression of the rubber type gaskets. Also, because the external components make use of the confining elements on the outer periphery of said gaskets, the need for periodically retightening the bolts is eliminated.
Hosokawa et al., U.S. Pat. No. 3,960,393 (1976) discloses a hose connector having a couple of connecting plates, a gasket pressed between the connecting plates, a pair of slightly curved plate pressures on the plates opposite to the gasket and fixing means for fixing the elements together.
Paullus et al., U.S. Pat. No. 3,772,637 (1973) discloses a device and method for sealing openings found on the rear faces of electrical connectors from which a number of electrical leads emanate. The invention is achieved by a layer of sealable material, such as an epoxy resin, attached to a rigid member to form a disk. Once formed, the disk can be pressed into a recess in the rear face of the connector, the pressure causing the material to flow into passageways and openings and sealing the electrical leads therein.
Dalgliesh, U.S. Pat. No. 1,890,497 (1932) discloses an apparatus for affecting the physical condition of gases comprising a circular plate with a plurality of perforations. The perforations are each sized to a diameter of 3-32 of an inch and are closely spaced to occupy substantially 62.5 percent of the total exposed area of the surface of a circular plate. The total area of the perforations cannot be increased beyond 70 percent or reduced below 50 percent without losing the advantages of the invention.
Greenwald, U.S. Pat. No. 1,797,954 (1931) discloses a refrigerant control which replaces a float valve and filter combination with a single means that is capable of serving as a filter and of giving equivalent resistance to that of a capillary tube or float chamber to control the supply of refrigerant from the condensing means to the cooling means of the apparatus.
Merrett, U.S. Design Pat. No. 348,924 (1994) discloses an ornamental design for a snap-in strainer. The design is comprised of a regular pattern of circular holes formed on a curved surface of a circular plate. Three connecting snaps are regularly spaced about the circumference of the strainer.
Jacuzzi, U.S. Design Pat. No. 290,166 (1987) discloses an ornamental design for a suction fitting for a hydrotherapy spa. The design is comprised of rows of regularly spaced slots circularly formed on the upper flat portion of a cylindrical surface and three rows of circular holes formed along the cylinder's curved surface. On the flat upper portion of the cylinder, the design provides space for two screws.
Mathis, U.S. Design Pat. No. 286,319 (1986) discloses an ornamental design for a guard for a water suction pipe having a plurality of circular holes formed on an upper surface. The guard is screwed into an interior threaded pipe.
None of these previous efforts disclose all of the benefits of the present invention, nor do these previous patents teach or suggest all of the elements of the present invention.